Very Interesting and Important Update: Due to some reason I just thought to do a complete new setup and this time I decided to again have openSUSE plus Ubuntu. So I first reinstall Lubuntu and then I installed OpenSUSE 12.2 (64 bit).

Now, my DSL speed is working very normal and fine on openSUSE. So this is very scary.

Is it possible for any operating system to manipulate my NIC so that it will work fine only on that operating system and not on another os?

Regarding positive thinking and not being paranoid, what is it that makes only openSUSE to get my NIC to work at normal speed but Ubuntu can not do it? Not even fedora? Not even Linux mint? What all these OS are lacking that enables openSUSE to work great?

This was my original question posted here:

I 'was' on opensuse 12.2 when my dsl speed was normal. Yesterday I switched from opensuse to Ubuntu 12.04 and speed decreased. It came to range of 7-10-13-20-25-kbps. Then I switch to linux mint, and then to fedora. Still slow speed. When I was in Ubuntu I disabled ipv6 but still no luck.

Now I am in fedora but this time with different ISP. And still I am getting very slow sped.
So my guess is this is nothing to do with os. What can be wrong?

Is this problem of NIC? Does NIC speed decreases over time? Does NIC life ends over time as with keyboard or mouse?

All the os I used are 64 bit and my laptop is Compaq Presario A965Tu Intel Centrino DUal Core.

Interesting thing to notice is I get normal speed while downloading torrent inside torrent client software. This slow speed issue applied to download from any web browser or installing software using terminal.

Yes I am getting packate loss in each ping. First time I tried I got 13%, second time 2% and third time 6% @tjameson
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Abhijit NavaleNov 24 '12 at 14:43

I had a problem similar to this that was related to MTU on my netbook. ifconfig eth mtu 1000 made it better, but this might not be the same thing. Compare settings from ip in both opensuse and lubuntu and see if there's anything different.
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RobDec 19 '12 at 16:29

It can be tricky telling the difference between ICMP de-prioritzation and packet loss, Rule of thumb is real packet loss doesn't go away on later hops.

Edit: ICMP is the protocol that runs Ping, Traceroute & MTR. Traceroute & MTR work by pinging each router along a path. Routers are just specialized computers, they have a certain amount of CPU & RAM power available.

When a router has high CPU utilization it priozities packets going through the router over ones going to the router, this de-prioritizing of ICMP, leads to deceptively higher latency when you ping that router rather than ping an upstream device (e.g. google.com)

@Abhijit - What about "CRC errors" from ethtool? Check MTR a few different times, if you keep seeing packet loss then there is some bad hardware somewhere. First I'd try to swap out the ethernet cable you are using, then try a USB wired NIC with a known good cable.
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JamesBarnettNov 24 '12 at 22:19

I dont get any CRC errors. Whats the ethtool syntax to get crc errors? Alos is bios poweron password has anything to do with this? becuase I have set bios poweron and admin password and after that this issue arise. @JamesBarnett
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Abhijit NavaleNov 25 '12 at 6:23